The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC manufacturing are needed. For example, for semiconductor devices, such as a metal-oxide-semiconductor field-effect transistors (MOSFETs), a stressor may be implanted on source/drain regions to strain the source/drain features (e.g., stressor regions) to enhance carrier mobility and improve device performance.
Forming epitaxial (epi) semiconductor materials on the source/drain regions is one of the existing approaches for enhancing carrier mobility and improving device performance. There is still a need to provide more stress on the source/drain regions to further improve the device performance.